Search

Sleep EEG variables were compared in an adolescent population consisting of 11 anorectic girls, 11 young depressed patients and 11 healthy volunteers matched for age and sex. Anorectic patients differed from depressed patients in a greater number and a higher length of awakenings. In comparison with controls, anorectic patients showed less sleep efficiency, a higher length of awakenings and less REM sleep. When anorectic patients were divided in restricting and bulimic subtypes, the bulimic anorectics showed an increase in stage 3 of sleep. These results do not support a direct association between eating disorders and affective disorders. Sleep EEG variables were not significantly correlated to the Body Mass Index.

Alterations of nocturnal sleep have been widely described in affective disorders. However, little is known about putative daytime sleep and to what extent daytime sleep could interfere with nocturnal sleep. The goal of this study was to investigate 24-hr sleep patterns in 12 depressed patients hospitalized for a major depressive disorder and in 10 control subjects studied under the same experimental conditions. Patients and controls were free to sleep whenever they chose, and sleep recordings were performed using the Oxford Medilog System during 60 hr. Daytime sleep episodes were detected in 50% of the patients and in 60% of the controls. Patients took naps at various times of the day, whereas controls napped in the early afternoon, during the well-known "postlunch dip". Thus daytime sleep prevalence was similar in both groups; however, the biphasic distribution of sleep observed in controls disappeared in the patients. Napping did not affect subsequent nocturnal sleep in either group.

Eight WHO research centres from Europe, North America and Asia took part in a WHO study aimed at assessing the reliability and consistency of sleep-EEG abnormalities in major depression. Each centre was asked to include in the study ten depressed patients aged 20-65 years meeting the Research Diagnostic Criteria for a major depressive disorder, and to match them by age and gender with ten controls. There were 67 patients and 66 controls included in the study. Compared with controls, depressed patients showed sleep-continuity disturbances such as increase in sleep-onset latency, and decrease in total sleep time and in sleep efficiency. Stages 2 and 3, as percentages of total sleep time, were reduced in depressed patients, REM latency was shortened and REM density increased. These findings confirm the presence of specific sleep-EEG abnormalities in major depression.

The comparison of polysomnographic data between a group of nine major depressive adolescents, 12 minor depressive adolescents and 12 controls showed a significant difference in sleep efficiency index and in percentage of awakenings. Sleep efficiency was reduced in major depressive adolescents and the percentage of awakenings was increased. Pubertal stage did not appear to have any effect on sleep EEG recordings. The administration of dexamethasone provoked a suppression of cortisol secretion in 50% of major depressive adolescents. Pubertal stage did not appear to have any significant effect on cortisol level after DST.

In the present study, deterministic and stochastic sleep staging (DSS and SSS) methods were compared with expert visual analysis in order to provide reliability estimates under strict conditions of comparison. Thirty polygraphic records (15 controls, 15 patients) have been investigated, including artefacts and doubtful periods. Average agreement rates of both methods compared to expert visual scoring were very similar, although a few specifics occasionally appeared for partial sleep stages. The comparison of more than 40,000 sleep decisions (on 20 sec epochs) yielded 75% absolute reliability for normal controls and 70% for pathological cases. However, if the agreement rate obtained for routine visual scoring (82%) in our sleep laboratory is considered as satisfactory, our system is then 90% satisfactory. Finally, complementary aspects outlined in the two automatic scoring systems suggested the development of a unique algorithm on the basis of these methods. Keeping in mind the size of the test sample and the strict procedure of comparison, the two automated staging systems described in this study can be used with reasonable confidence for large scale investigations of sleep in man.

In the present paper we will comment on how we have been implementing computer-aided sleep staging (CAS) in the Department of Psychiatry, Erasmus Hospital (Free University of Brussels). Major features of our CAS include real-time stage estimation, full report and hypnogram available in the morning, and evolution of state variables throughout the night (e.g. electroencephalographic spectral characteristics, eye movement density, myographic activity). Parallel, we report an extensive validation study of this system on 50 subjects divided in two groups of 25 patients with psychiatric diseases, and 25 normal subjects.

After one accommodation night, sleep EEG recordings were performed during three consecutive nights in ten drug-free inpatients presenting generalized anxiety disorder (GAD) with significant depression, compared with a age- and sex-matched group of patients with GAD and a group of primary major depressive disorder (MDD) patients. GAD patients with depression did not differ from GAD patients in any sleep variable. Patients with MDD showed more stage shifts and a greater number of awakenings than patients with GAD. REM latency was significantly shorter in MDD patients than in the other groups, and may thus help to differentiate anxious from depressed patients.

Sleep polygraphic recordings were performed during 3 consecutive nights in 12 inpatients with generalized anxiety disorder (GAD) in comparison with age- and sex-matched groups of patients with major depressive disorder (MDD) and normal subjects. GAD patients differed significantly from those with MDD. A lower number of awakenings and stage shifts in night 1 and the mean of the 3 nights and a shorter rapid eye movement (REM) duration in night 1 but longer REM latency in the mean of the 3 nights were observed in GAD in comparison to MDD. GAD patients also showed a significantly longer sleep onset latency and shorter duration of total sleep time and Stage 2 than control subjects. Electroencephalographic sleep recordings, as well as other laboratory tests, may help the clinician to differentiate anxiety from depressive disorders.

Sleep polygraphic recordings were performed during 3 consecutive nights in a sample of 43 affectively ill inpatients. The patients were classified as major (n = 36) or minor depressive disorder (n = 7), according to the Research Diagnostic Criteria. Among the 36 patients with a major depressive disorder, 14 were in remission at the time of the sleep investigation. A two-way analysis of variance was performed to assess night and diagnostic effect on sleep variables. Shortening of REM latency was observed in depressed patients with major depressive disorder when compared to major depressive disorder patients in remission. Depressed patients with major depressive disorder also showed higher REM activity and REM density values than patients with minor depressive disorder. According to the linear discriminant analysis, sleep variables were able to correctly classify 68% of the patients.

Sleep polygraphic recordings were performed in six unmedicated male manics, in age and sex matched unipolar and bipolar depressives and in normal controls. No difference was evidenced between manics, depressives and controls when percentages of sleep stages 1, 2, 3, 4 and REM were considered. Manics demonstrated poorer sleep efficiency, longer sleep onset latency and reduced sleep period time than normal controls but no more so than in our depressed patients. None of the classical sleep disturbances reported in depression (short REM latency, decreased delta sleep and increased REM density) were observed in mania suggesting that with the exception of sleep continuity disturbances, sleep in mania is comparable to sleep in normal subjects.